The effect of internal tides on the vertical structure of tidal current in the North Huanghai Sea

The tidal current is generally predominant in China's offshore areas.The vertical structure of the observedtidal current is quite complicated with the presence of seasonal thermocline.The observed tidal current may be divided into two parts,an averaged barotropic tide current and a variation tide current.A method for studying the vertical structure of tidal current is developed from the constitution and distribution of energy,and the vertical structure of the observed tide current in the North Huanghai Sea is studied on the basis of the method.The result shows that the reason why the energy of the tidal current is concentrated on the neighbourhood of the thermocline mainly lies in the internal tides i under certain conditions,the fact that the direction of the internal tide current above the thermocline is opposite to the one below the thermocline will be able to cause the rotary directions of the observed tidal current above and below the thermocline to be in opposite.